MgO tablets are used as a co-catalyst in the metathesis reaction of butene with ethylene to form propylene. The metathesis reaction to form propylene includes the following reactions:
MgO accomplishes the isomerization of 1-butene to 2-butene and adsorbs poisons in the feed stream such as H2O, CO2, oxygenates (such as methyl tertiary butyl ether or MTBE), sulfur compounds, nitrogen compounds, heavy metals and the like.
Isomerization catalysts in tablet form exhibit a crush strength that permits the catalyst to withstand the pressures and stress that are exerted on the catalysts during use. However, the manufacture of tablets is costly and time consuming. In addition, the formation of tablets having complex shapes is difficult or not possible.
Accordingly, there is a need for an isomerization catalyst that can be provided in a different form from tablets and that maintains an acceptable isomerization activity after aging. There is also a need for isomerization catalysts that exhibit acceptable crush strength so the catalyst can withstand the pressure of hydrocarbon flow in the catalyst system as well as the stress placed on the catalyst when packed into a reactor.